Brewers in the Capital Region are embracing the trend of sour beers. Toeing the line between mistakenly produced vinegar and delightfully cheek-puckering brews, the popularity of sour beer is the grown-up version of sucking on tart candies that make eyes water with aggressive acidity before giving way to sweet pleasure.

Sour beer is done in an old style, tracing roots back to Flemish red ales, Belgian farmhouse ales and lambics and the Berliner weisse. Using naturally occurring bacteria, the style of sour beer is more broadly characterized as wild- or mixed-fermentation beer, sometimes aged in barrels or allowed to further ferment in bottles. The beer is typically not pasteurized like other commercially produced beers. "That whole style of beer, that philosophy of beer, has grown in American brewing," said David Gardell, a brewer and owner of The Ruck, a craft beer-focused bar in Troy. Over the past year, the number of tap lines at The Ruck dedicated to sours has grown from three to eight of the 33 lines, he said.

That growing popularity will be the focus of Saturday's Fall Fermentation Fest at Common Roots Brewing Company in South Glens Falls. This is the second year for the beer festival, which Common Roots co-owner and head brewer Christian Weber said started unexpectedly. "We called it a 'fest' but didn't have the intention of a festival," he said, referring to the surprise of 400 people showing up last year when he debuted a new sour beer and invited a few like-minded brewers to offer some of their sour beers, as well.

This year's festival will include 20 breweries from around New York and the Northeast in a typical beer fest format focused on what Weber called "the wild side of beer." Food will be available for purchase from the City Beer Hall and YesFolk Tonics, of Troy, will be serving non-alcoholic fermented tonics, water kefirs and kombuchas. The Fall Fermentation Fest is different from other festivals, said Weber, because, "this beer festival is very specific. I think there are a lot of really great beer fests and nothing against clean-cultured beer, but we wanted to celebrate sours and wild fermentation."

That clean culture he referred to is the general term for beer that uses yeast that was controlled and grown in sterile environments, creating a certain flavor profile that leads to IPAs, stouts, bocks and lagers. With "wild beers," the initial brew of the beer (called wort, before it is fermented and becomes beer) is left in a large stainless steel pan called a coolship to be spontaneously inoculated with the yeast and bacteria that exists in the air, or is mix-fermented with those wild yeasts and controlled yeast from a laboratory.

Several regional breweries have experimented in the wild and sour genre: Rare Form Brewing Company in Troy produces Sour in the Sage and Family Tree Sour Brown; Brown's Brewing Company in Troy has a Wild Ale Series of seven different sour ales; Great Flats Brewing in Schenectady makes a cranberry lime sour, while Shmaltz Brewing Company in Clifton Park has long been known nationally as the maker of Funky Jewbelation, a sour barrel-aged beer. Druther's Brewing Company, with locations in Saratoga Springs, Albany and Schenectady, was one of the first breweries in the area to regularly produce a sour style known as gose (pronounced GOES'-uh) that uses lactobacillus and pediococcus yeasts, producing a salty-sour and light lemon flavor. Other wild sour beers occur when brettanomyces, a natural bacteria, inoculates the wort and creates a "funk" in the beer, sometimes affectionately referred to as "horse blanket." (Deliciously, of course.)

Gardell describes some of the flavors of sour and wild beers as "9-volt battery to the tongue," and "jowl-shocking," but says that it is nearly impossible to produce wild- or mixed-fermented beers with the same results each time. Brewers he speaks to say that microbes in sour beers are like children in a household. "At any time, one child might have more of an impact than the others."

Weber is debuting the new version of his Rooted series of beer, which is fermented in his coolship, a piece of equipment not in common use by breweries in the region. The beer is released twice a year and is different each time based on the natural environment and terroir (flavors derived from natural factors unique to an area of origin) present at time of brewing and inoculation. The beer is aged in barrels and in bottles before release, and is available only at the Common Roots brewery. Weber expected most bottles (in 375 milliliter and 1.5 liter sizes) will be bought during the Fall Fermentation Festival. The beer, said Weber, is made with all New York state raw materials

Weber called his line of wild-fermented beer, which also includes the Branch series of blended barrel-aged beer and Representation of Wild Things, which is made in collaboration with other breweries and restaurants, as "super selfish of me," to produce but "one of the most innovative things we do." Wild and sour beers have a higher chance of spoiling and becoming undrinkable, take more space to produce and age and more time to perfect, and "don't pay the bills like IPAs do," Weber said. Common Roots produces 5,000 barrels of beer a year but is expanding its facilities to produce more wild and sour beers.

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